An apparatus is provided for supporting an expansion tank and, more particularly, a bracket is provided for attachment between an expansion tank and an associated hot water heater or adjacent structure.
Expansion tanks are used in domestic water systems particularly to protect hydronic or thermal (hot water) heating systems. An expansion tank is required when the water system includes a backflow prevention device such as a check valve, a pressure reducing valve, or other means of reduced pressure backflow protection. The tank is a manufactured cylindrical vessel normally possessing slightly rounded ends and typically made of steel or other rigid material, which conventionally may be rated to take an internal pressure of up to 200 pounds per square inch (psi). The expansion may be provided with a pipe nipple usually at the center of one end for connection to the plumbing, thereby permitting water and any entrained air to enter and exit the tank. The expansion tank houses an internal expandable rubber bladder to separate the water from a cushion of pressurized air within the tank. An air valve often placed at the opposite end of the tank permits a plumber or installer to adjust the air pressure behind the bladder to correspond as needed to the normal system water pressure. In the absence of the air valve, a predetermined back pressure is applied to the bladder during manufacture.
Thermal expansion tanks extend the life of water heaters and similar equipment. Expansion tanks may also be used to eliminate the phenomenon known in the trade as “water hammer”, caused when a plumbing system vibrates and emits loud knocking noises due to water surging against trapped air pockets in the piping. They may heat and cool periodically and may change weight by virtue of the varying contents during intermittent usage. Because the tank partially fills with water during use, a typical tank used in the home may weigh up to ten pounds or more. In commercial installations, an expansion tank may weigh up to 20 pounds or more during use.
Expansion tanks may be installed in either a vertical, horizontal or occasionally other orientation. Since expansion tanks can fail over time and may need to be changed periodically, or the connections to the tank may need to be replaced, a simple and quick means of access and replacement is desired.
The expansion tank, as well as the piping to which the tank is connected, may expand and contract very slightly with temperature changes. Means for supporting the tank must allow for such very slight expansion and contraction without permitting major disruptive movement. Vibration should also be minimized as it could be deleterious to the piping system leading to premature failure. Vertically mounted tanks should be well secured to prevent tipping as the internal weight changes.
According to manufacturers' instructions and official plumbing requirements, a thermal expansion tank must have an external means of support other than the piping. This is particularly necessary when piping other than hard metal piping is used. Currently there are no known official standard prescribed ways of furnishing such means. As commercial piping itself has evolved over time from hard metal piping to more modern, less expensive systems utilizing flexible plastic piping, the means of support for the expansion tank becomes even more critical to prevent the tank from moving significantly, tilting, twisting or becoming disconnected during use due to flexing of the piping and filling and emptying of the tank as well as possible disruptions in the surrounding area. Custom arrangements whereby hard piping must unavoidably be used to support the tank in the vicinity of the water heater, followed by flexible plastic piping elsewhere in the system, become more expensive, time-consuming and cumbersome to install.
Some custom support means currently employed in the art for expansion tanks include use of various types of metal or plastic strapping to joists, rafters, columns, studs, pipes, posts, or similar structural means within the building structure, wiring the tank to such structural means, cradling the tank between parallel or other pieces of lumber or similar support means that are custom-installed on site, building a shelf under the expansion tank, and similar miscellaneous means that may vary with the job situation and the individual experiences of the plumber or installer. All such custom on-site installation methods are time-consuming and therefore costly, can change with conditions encountered on the individual job and location where the tank is being placed, and may not pass official inspection.
Plumbing codes prevent use of support means that would violate the integrity of the manufactured tank itself such as welding or brazing a piece of metal to the tank, fastening a bracket to the tank by means of screws or fasteners that would penetrate the wall of the tank, or similar such means that may lead to tank failure and subsequent safety hazard or damage to the surroundings. Since the tank is usually coated with a surface protection means such as paint to prevent external corrosion, thereby extending the life of the tank, it is undesirable to employ a support means that would damage that surface protection.
Adhesive means such as gluing or duct-taping the tank to a building structural member or other point are generally impractical and would not survive over an extended period of time, due to repeated weight changes plus slight expansion and contraction with thermal changes of the tank as well as aging of the adhesive means, nor pass official inspection.
Finally, tanks that are installed on a nearby wall or other surrounding structure should have some sort of separate overflow or rupture protection to protect the surroundings against flooding should failure occur, often mandated by inspectors, architects or official code. Tanks installed on the water heater itself can benefit from use of the same drainage tray typically used on the floor under water heaters and increasingly required in modern installations, including where such heaters are installed on upper floors or in water-sensitive areas of a building. Similarly, any alarm system installed to warn of failure of the water heater could also detect any problem with the expansion tank, rather than needing a second system.
For the foregoing reasons there is a need for a simple, compact and inexpensive apparatus to affix a thermal expansion tank directly to a moveable free-standing structure, such as a residential, commercial or industrial hot water heater. The expansion tank may be installed above the heater in a vertical, horizontal, or other orientation such that any means that has been installed to protect the surroundings from flooding and water damage due to failure of the heater, such as an overflow drainage tray installed under the heater or a flood alarm system, can simultaneously protect against any failure of the expansion tank without requiring separate flooding protection as would be needed for tanks located remotely from the water heater, including those mounted on a nearby building structural member. The apparatus for affixing the expansion tank should simplify and require minimal use of time to install the apparatus, minimize the space required for the apparatus, not damage the integrity or surface coating of the tank while making it integral to the hot water heater, minimize the length of piping attaching the tank to the heater, and meet all official plumbing requirements for installation of such a tank. Since the expansion tank will change weight during use, the apparatus should permit the tank to change weight or expand and contract slightly in normal repetitive usage without detaching itself from the apparatus holding it, or causing other damage to the plumbing system or the surroundings. Stress and strain on the piping system connected to the tank should also be minimized by not forcing the piping to bear the weight of the tank and its contents, thereby allowing the use of modern flexible plastic piping if desired rather than metal piping which is more expensive and more difficult to assemble, and to prevent said piping from detaching itself from the tank or suffering breakage or leakage due to such stress and strain. Finally, the new supporting apparatus should allow the tank to be easily removed from such apparatus for replacement when the tank fails or is due to fail because of age or continued use, and to easily reinstall a replacement tank without unnecessary dismantlement of the supporting apparatus or time-consuming cleanup or refurbishing of the apparatus.